feat(db): add session-vector capture queries; LikeTrack returns row count

ListRecentSessionTracks + UpdatePlayEventVector for the vector capture
path inside RecordPlayStarted. LikeTrack switches to :execrows so the
contextual-likes capture can detect insert vs already-exists. Existing
callers updated to ignore the count for now; later tasks consume it.

internal/db/dbq/events.sql.go

@@ -188,6 +188,60 @@ func (q *Queries) InsertSkipEvent(ctx context.Context, arg InsertSkipEventParams
 	return i, err
 }
 
+const listRecentSessionTracks = `-- name: ListRecentSessionTracks :many
+SELECT t.id, t.title, t.album_id, t.artist_id, t.track_number, t.disc_number, t.duration_ms, t.file_path, t.file_size, t.file_format, t.bitrate, t.mbid, t.genre, t.added_at, t.updated_at FROM tracks t
+JOIN play_events pe ON pe.track_id = t.id
+WHERE pe.session_id = $1
+  AND pe.started_at < $2
+ORDER BY pe.started_at DESC
+LIMIT $3
+`
+
+type ListRecentSessionTracksParams struct {
+	SessionID pgtype.UUID
+	StartedAt pgtype.Timestamptz
+	Limit     int32
+}
+
+// Returns up to $3 tracks in session $1 whose play_event started before
+// $2, ordered newest-first. Used by playevents.RecordPlayStarted to
+// build the session_vector for the just-inserted play_event.
+func (q *Queries) ListRecentSessionTracks(ctx context.Context, arg ListRecentSessionTracksParams) ([]Track, error) {
+	rows, err := q.db.Query(ctx, listRecentSessionTracks, arg.SessionID, arg.StartedAt, arg.Limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []Track
+	for rows.Next() {
+		var i Track
+		if err := rows.Scan(
+			&i.ID,
+			&i.Title,
+			&i.AlbumID,
+			&i.ArtistID,
+			&i.TrackNumber,
+			&i.DiscNumber,
+			&i.DurationMs,
+			&i.FilePath,
+			&i.FileSize,
+			&i.FileFormat,
+			&i.Bitrate,
+			&i.Mbid,
+			&i.Genre,
+			&i.AddedAt,
+			&i.UpdatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const touchPlaySessionLastEvent = `-- name: TouchPlaySessionLastEvent :exec
 UPDATE play_sessions
 SET last_event_at = $2,
@@ -251,3 +305,21 @@ func (q *Queries) UpdatePlayEventEnded(ctx context.Context, arg UpdatePlayEventE
 	)
 	return i, err
 }
+
+const updatePlayEventVector = `-- name: UpdatePlayEventVector :exec
+UPDATE play_events
+SET session_vector_at_play = $2
+WHERE id = $1
+`
+
+type UpdatePlayEventVectorParams struct {
+	ID                  pgtype.UUID
+	SessionVectorAtPlay []byte
+}
+
+// Used right after InsertPlayEvent to populate session_vector_at_play
+// once the vector has been computed.
+func (q *Queries) UpdatePlayEventVector(ctx context.Context, arg UpdatePlayEventVectorParams) error {
+	_, err := q.db.Exec(ctx, updatePlayEventVector, arg.ID, arg.SessionVectorAtPlay)
+	return err
+}